Apparatus for reclaiming used foundry sand



Ailg. 3o, 1949.

R. 1 LUCE ETAL APPARATUS FOR RECLAIMING USED FOUNDRY SAND Filed Junev 28, 1945 wem:

Sig

Patented Aug. 30, 1949 stm-iras A' PPRATSR RECLAIMG'VUSD "fFOUNDRYJSAN'D i 'R'y'fL fLtxcefand Adliian Den-iBreejenyChicago;ill., assignors to The Hydro-Blast fConporaton, "Chicago, `Ill., a-ccrporaton oflllinos Application ne 28, 1945,"5SeiiialillofFGllZ'fG solaires. (Ciac-39) zinvention relates to'appaatusor reclaim'- ing ii's'ed foundry-sandiand linore 'particiilarly'-fto thef`tfatii1'nt of foundry sands-to remove Clay, ities; brnedf binder and other foreign materials "-'io'ji'fod 561e aifif's'aiditable 'f 012 reuse.

Variousproposals :have heretofor'e'been made 'forrclaiinin'g foundry s'ands for reuse by :remo-val Z(if*clays,-'1i'ne's,`lzindingiriaiterialand the-like thereffiiin. Yone prposesy'stemthe used sand'has rubbed to'flo'o'sen'fthe undesired fmaterial 'efsan'dv andh'as thereafter been classified gto `s1oarate the'i's'and'lfrom-the loosened material. For many types of sands systems of this type have 'been "lfundf entirely satisfactory but other -byisdf b'an'd's Ehave not hbe'ifi adequately A'Cleaned bastion-systems. A

Wife'have found that those-sands ``which are Vnot hproperly cleanedbyprior scrubbing systems gen'- -eral-ly' contain 'relatively large 'quantities Aof v"clay, nes land the -llike land that the 4'presence fof ysuch materials Cushions 'the sand grains duringscrub- 'bin'g -sothat burned binder,v fclay and 'rines adfheing Ato the'grainsare notloosened during the scrubbing operation. A-It isiaccordingl'y one ofthe nbjectsof fthe Apresent linvention to 7provide apparatus `for reclaiming yusezl ff'oun'dry sand andfthe llike'linut/nichfree'- clay, fines and other 'foreign"materials are removed vfrom 'thesand prior to scrubbng s'olthatifectiveness of the scrubbing oper- "ationwillbe increased. I'

"Another 'object 'is' "to pr'ovidepapparatus -for 're- 'claimingsand in-which 'thesandgissubjected to a preliminary wet 'classfication -`before scrubbing itu vremoveY free4 'clayand fines which might interfereL withsciubbing.

A further object is 'to"provide apparatus in which the' silica'ines removed from the sand may be separated-from the clay and the like and recovered when desired.

IAThe above' and other'objectsandlaldvantages 'of the invention will be more readily? apparent Zirom the followingdescription when readin connection with t'he accompanying drawing,` in Which- Thelsingle gure is a diagrammatic view fo'ffa sand i'reclaiming apparatus Vembodying the i i inventicn. A

ln tl-1e' apparatusfas shown, lu-sed foundtyfs'and which 1i'sua1ly-contains-clayi silica finesjburn'd biiider'rnterialand-otherforeignimaterialsfisifed into a1 -lump'f-breaker lUthrou'ghf'aiSupply-conduit iidic'ted Aatl I. Simultaneously-Water is supplied to the lump breaker through a pipe I2. The lump breaker may be a conventional type device and may normally include a rotatable drum in which the sand and water are tumbled to mix them and 4that'Walter will 'r'ainiro'mfthe sandand .the

to fbreak-upanyrsand Jlump's, such as piecesmf icoresfand 'the like. 'I-'helumptbreaker fformsea now-able mixture :of fthe-sand rand water @which fiscollected `in la :trough ll S-:and fied \.toawibratng screen |11.` Any :unbroken 1umps,.,piecesfof tramp metal'rand .the like are eseparated :fromfthe :sand `and water mixture ybyolie-screen. --SIhexsa-ndimixture is Acollected from .the screenincastorage sbin or container 'i5 fWhile-rthezflumpsf iandwothr .imaxterial which will netpass thascreencanerdeli-vered xto abin 4B. Y

. From the ,r storage mira-tiifetheA flowableanixture orf sand-.and water ismumpe'd throughffa condmt lil bysafpump I-8 intona 'liquid .type classier 4:9. The. classierasshown is ofthe type sinswhicham upow of Water through cones 2| carries :upward material .whichsis .lighter-or smallerllthanithe sand grains lWhile lpermittinghtheeA sandegrains-iw now down'through thel .upwardeurrent of water into =ahopperf 22. The light umaterial :carried up through` -the cones `Lincluding .the .free eclay,-A nes and other lig'ht .or small foreign 4particles l.mathe mixture is ydischarged over the .top of, .the classifier Athrough 3a. pipefB. Y

Fromthelhopper ..22'the sand .andowater :mixture which 'is still ofyflcwable consistency containing .`aboutl30% water .is delivered through .a con'duit'2'4 into a- 'dew'ateringftank v25. The..de watering tank, as s'hown,'has anangular bottom 26 along 'which a .conveyer 21 moves 'the .sand so 'sand 'willfbe 'discharged at the top. of the conveyer with a water content .of .approximately sand`from Whichall of the".f1ee clayrifd 'i'lnes 'have 'been removed is delivered to. afscrubber ZBWliiclr may be "ofthe type more particularly `described and claimedvin A*the :eo-.pendinelamili- 'cationfof v"lren l'Breejen' Serial No. 436;760,1d 'March '30, 1942, :now matured into "Patent No. 2,3833'045, granted August 21; 1945. This scriibm LAber; as illustrated, comprises a 'rotating barrel 'in which an'fel'ongarte'd weight '29is loosely supported "commiseY theA sand grains to.. scrub Vagainst each 'other' as the barrel vis rotated. Due to "the 'fact that allV freeclay and nes.V have been removed fro'mfthe sand .byftheclas'sier I 9 before it is 'delivered` to the 'scrulciberfa very effmien't scrubbing action is Aproduced'which will vloosen from the sand-'grains' `clay *nesflourne'd binder and light maten-a1 which adheresitherto. "rims, 'by vthe time the material is"discharg'e`d"cf1-om`thescrubL ber, the sand grains are cleaned and the discharged mixture contains only .clean sand grains and free clay fines, burned binder and the like.

As explained above, We have found that initial removal of the free clay and fines substantially improves the effectiveness of the scrubber shortening the time required to clean the sand grains and producing a more complete cleaning operation.

The scrubbed V'mixture is discharged from the scrubber into a hopper- 3l which isv supplied with water through a pipe 32. Conveniently, the pipe 32 may connect to a trough 33 which catches the overflow water from the dewatering trough 25. The addition of Water returns the mixture to iiowable consistency so that it can be pumpedfby a pump 34 through a pipe 35 into a second classier 36 which may be similar to the classifier 19. The classifier 38 is so adjusted that only clean sand grains larger than a predetermined size will drop through its cones 3'1 While all clay and silica nes which are ner than the desired end product -duit 42 into a drum drier 43 in which it is reduced Vto anydesired state-'of dryness. Y From the drum dried 43 the cleaned and dried sand is discharged at 44 and may be collected and reused in any -desired manner.` WeV have found that sand treated Vaccording to the present invention is -clean and sharp and is in a highly desirable state for foundry use. v According to a further feature of the present invention, the silica iines, which are discharged at the tops of the classiiers I9 and 36, may be recovered when desired to beused as silica flour. For this purpose, as shown, the pipes 23 and 38 discharge intoa dew'atering device 45 similar to the dewatering device-25. The dewatering device 45 includes a conveyor 46'for carrying the solid materials out of the Water and for discharging them intoa hopper 4l. lIn the hopper l additional water vis added through a pipe 48 to form a owable mixture which is pumped through apipe 49 by a pump 5l into a classier 52. The classier'52 maybe of the'` same general type as the classifiers I9 and 36 but so adjusted that it will reject the clay and pass the silica iines 'through its cone 53 into a dewatering device 54.

The silica nes are draggedfrom the dewatering tant: 54 bya conveyer 55 andY discharged to a drier 56 in which theycan be reduced tov any desired state ofdryness. :The .product recovered from this drier .will be a fine sand Whose iineness depends -upon the settings of Vthe several classifiers and which corresponds in general to the silica ilour used in foundries. It will be apparent that in cases Where recovery of the silica nes is not desired, the material overowing from the "classiiiers i9 and 36 can be discharged directly `to waste. p

While one embodiment of the invention has beeny shown and described in detail herein, it will be understoodthatthis-is illustrative only and ",is'not intended as 'a denition of the scope of the invention, reference being had for this purpose to the appended claims. Y

type classier receiving the scrubbed material from the scrubbing means to separate the loosened fines and foreign material from the sand, and 'drying means receiving the sand from the second classifier to dry it.

2. Apparatus for reclaiming used foundry sands and the like comprising means for mixing the sand with water to form a owable mixture, a liquid type classifier receiving the flowable mixture for separating free clay and lines from the mixture, dewatering means receiving from the classier the portion of the classified mixture containing the sand to dewater the sand to a substantially mushy consistency, a scrubber receiving the dewatered sand mixture from the dewatering means to loosen adhering fines and foreign material from the sand grains, a second liquid type classifier receiving the scrubbed mixture from the scrubber to separate loosened nes and foreign material from the sand, and drying means receiving Vthe sand fromrthe second classifier to dry it. v

Y 3. Apparatus forV reclaiming used foundry sands andthe like comprising means for ymixing the sand with water to form a iiowable mixture, a liquid type classifier receiving the ilowable-mixture for separating free clay and fines from the mixture and for separately discharging the portions of the mixture containing the sand and the clay and fines, a scrubber receiving the portion of the mixture containing the sand to loosen adhering iines and foreign material from the sand grains, a second liquid type classifler receiving the scrubbed material from the scrubber for separating the loosened fines and foreign material from the sand and for separately discharging the portions of the mixture containing the sand and the loosened fines and foreign material, drying means receiving the portion of the mixture containing the sand to dry the sand, and a third classier receiving from the first two named clas- Asirlersf the portions of the mixtures containing the clay, lines and'foreign material to separate the fines from the clay andforeign material.

ROY L. LUCE. ADRIAN DEN BREEJEN.

REFERENCES CITED The following references vare of record in the le of this patent:

UNITED STATES PATENTS Christensen May13, 1947 

